Problem: Evaluate the following expression when $b = 8$ and $a = 6$. $7$ $b$ $ + 5$ $a$ $ - 5$
Solution: Substitute $8$ for ${b}$ and $6$ for ${a}$ $ = 7{(8)} + 5{(6)} - 5 $ $ = 56 + 30 - 5 $ $ = 81$